During processing and assembling of a workpiece, it is usually required to measure the verticality between two structures of the workpiece, to determine whether the workpiece meets the processing, assembling, and other requirements. The existing verticality measurement tools mainly comprise square, three-coordinate measuring machine, plumb bob, laser measuring instrument, etc. These instruments are usually simple in structure, and can be used for the measurement between a straight line and a plane, and a plane and a plane. However, many workpieces are complicated in structure, the conventional verticality detection devices may be difficult to be placed properly in the workpieces for measurement, or the measurement process is too complicated, or the measuring tools are too expensive, so that the conventional simple verticality detection devices cannot be well applied to the assembly process of the workpieces. Although some verticality measuring devices may measure the verticality of the workpieces, the results of measurement cannot be displayed intuitively.